1. Field of the Invention
The present invention relates to the field of intelligent assist devices (IAD), and in particular, to a practical intelligent assist device (PIAD) that can interact with human operators in a practical, easily maintainable fashion.
2. Description of the Related Art
In an industrial application such as a manufacturing assembly line or general material handling situation, the payload may be too large for a human operator to move without mechanical assistance or risking injury. Even with lighter loads it may be desirable to provide a human operator with mechanical assistance in order to allow more rapid movement and assembly, avoid strain, fatigue or repetitive motion injuries. Thus, a great deal of industrial assembly and material handling work is done with the help of personnel assist devices.
Intelligent Assist Devices (“IADs”) are a class of computer-controlled machines that interact with a human operator to assist in moving a payload. IADs may provide a human operator a variety of types of assistance, including supporting payload weight, helping to overcome friction or other resistive forces, helping to guide and direct the payload motion, or moving the payload without human guidance. The Robotics Industries Association T15 Committee on Safety Standards for Intelligent Assist Devices describes IADs as a single or multiple axis device that employs a hybrid programmable computer-human control system to provide human strength amplification, guiding surfaces, or both. These multifunctional assist devices are designed for material handling, process and assembly tasks that in normal operation involve a human presence in its workspace. Typically, Intelligent Assist Devices (IADs) are force-based control devices that range from single axis payload balancing to multiple degree of freedom articulated manipulators.
However, the use of forced-based control in particular, and intuitive directional control in general, can lead to many practical problems on the factory floor. Such systems and devices are complicated, both electronically and control wise. These systems must estimate or predict the control functions of the operator from limited inputs, and these limited inputs are subject to ambiguity, interference, and downright failure. For example, with only one physical input, i.e. force applied to a load cell on the operator control, an IAD will need to gauge and predict the desired direction (in both “x” and “y” planes) and speed, while at the same time taking into account vibration within the facility, structural interferences of the assembly line, safety of the operator (position relative to direction of travel), variations among different individual operators and, possibly, unintentional input by the operator. The typical commercial response to these challenges has been an over technical, over engineered control algorithm that requires complex damping, calibration, and tuning. Further, such solutions require constant re-assessment in a manner that is difficult for the arena in which they are operated. In other words, typical facilities do not have the technical resources or proprietary know-how for maintaining such devices.
A need exists to provide a practical intelligent assist device (PIAD) to merge the best of the powered assistance currently available with current IAD's, but with an easier to program and maintenance characteristics. Consequently, a need has been felt for providing an intelligent assist device that is direct and easy to operate, while at the same time being capable of being programmed, tuned, and maintained without the need of specialty hardware or technical resources that are generally unavailable in most manufacturing settings.